| 摘要 |
PURPOSE:To improve the corrosion resistance of a permanent magnet by providing a corrosion resistant vapor-phase aluminum plating layer and a Cr acid salt coating layer on the sintered permanent magnet which mainly contains R (R is at least one of rare earth elements including Y) B and Fe, and tetragonal crystal of main phase and filling a resin in the fine pores of the phase. CONSTITUTION:Rare earth elements R are included in a range of 10-30atom%. If less than 10atom%, high magnetic property and hence high coercive force is not obtained, and if more than 30atom%, its remaining magnetic flux density Br decreases. B is included in a range of 2-28atom%. If less than 2atom%, high coercive force (iHc) is not obtained, and if more than 28atom%, its remaining magnetic flux density Br decreases. Fe is included in a range of 65-80atom%. If less than 65atom%, the remaining magnetic flux density Br decreases, and if more than 80atom%, high coercive force is not obtained. After the surface layer of the sintered magnet is removed, the surface of the magnet is covered with a thin aluminum or zinc thin corrosion resistant plating layer, and then shot peened. After the surface of the magnet is treated with chromium acid salt, impregnated with thermoset resin, cleaned, dried and then thermoset. |
